Highly Efficient Performance and Conversion Pathway of Photocatalytic CH₃SH Oxidation on Self-Stabilized Indirect Z-Scheme g-C₃N₄/I^3–-BiOI

Abstract

A self-stabilized Z-scheme porous g-CN/I-containing BiOI ultrathin nanosheets (g-CN/I-BiOI) heterojunction photocatalyst with I/I redox mediator was successfully synthesized by a facile solvothermal method coupling with light illumination. The structure and optical properties of g-CN/I-BiOI composites were systematically characterized by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, X-ray photoelectron spectroscopy, N adsorption/desorption, UV-vis diffuse reflectance spectrum, and photoluminescence. The g-CN/I-BiOI composites, with a heterojunction between porous g-CN and BiOI ultrathin nanosheets, were first applied for the photocatalytic elimination of ppm-leveled CHSH under light-emitting diode visible light illumination. The g-CN/I-BiOI heterojunction with 10% g-CN showed a dramatically enhanced photocatalytic activity in the removal of CHSH compared with pure BiOI and g-CN due to its effective interfacial charge transfer and separation. The adsorption and photocatalytic oxidation of CHSH over g-CN/I-BiOI were deeply explored by in situ diffuse reflectance infrared Fourier transform spectroscopy, and the intermediates and conversion pathways were elucidated and compared. Furthermore, on the basis of reactive species trapping, electron spin resonance and Mott-Schottky experiments, it was revealed that the responsible reactive species for catalytic CHSH composition were h, O, and O; thus, the g-CN/I-BiOI heterojunction followed an indirect all-solid state Z-scheme charge-transfer mode with self-stabilized I/I pairs as redox mediator, which could accelerate the separation of photogenerated charge and enhance the redox reaction power of charged carriers simultaneously.

Micro‑meso-macroporous FeCo-N-C derived from hierarchical bimetallic FeCo-ZIFs as cathode catalysts for enhanced Li-O2 batteries performance

“…S4). The increased size of M-FeCo-ZIFs-X nanocrystal precursors is attributed to the elevated Gibbs free energy caused by lattice distortion of partial substitution of Co 2 + by Fe 2 + , which was consistent with previous reports [43] . The surface of the M-FeCo-N-C-X got rough and wrinkled while remained the original morphology of M-FeCo-ZIFs-X after the high thermal treatment ( Figs.…”

“…The M-FeCo-N-C-X catalysts were prepared by slightly modified from previously reported methods [43] . In typically synthesis, 0.500 g PS templates, specific feedings of Co(NO 3 ) 2 ·6H 2 O and FeSO 4 ·7H 2 O were dissolved in 160 methanol to sonicate 60 min.…”

Experimental method to explore the adaptation degree of type-II and all-solid-state Z-scheme heterojunction structures in the same degradation system

“…This type of study has greatly enriched the theoretical understanding of photocatalysis. Heterostructure (including Type-I and Type-II heterojunctions [9]), Z-scheme heterojunctions (including direct Z-scheme [10], and indirect Z-scheme heterojunctions [11]) have been proposed as mechanistic explanations of performance enhancement. Currently, two kinds of heterostructures are popular and are briefly introduced below.…”

Advanced Two-Dimensional Heterojunction Photocatalysts of Stoichiometric and Non-Stoichiometric Bismuth Oxyhalides with Graphitic Carbon Nitride for Sustainable Energy and Environmental Applications

“…Similarly, ethylene glycol assisted solvothermal synthesis reported by Ji et al for the fabrication of ultrathin Bi 4 O 5 Br 2 nanosheets dispersed over layered g-C 3 N 4 also exhibited higher photocatalytic activity for ciprofloxacin decomposition under visible light irradiation [85]. Another report on solvothermal synthesis was reported for the synthesis of g-C 3 N 4 /I 3− -BiOI heterojunction semiconductor using self-stabilized I 3 − /I − as a redox mediator that efficiently strengthened the interaction between porous g-C 3 N 4 and ultrathin BiOI, thereby enhancing their photocatalytic activity in CH 3 SH oxidation [63].…”

“…The open crystalline structure has a layered Sillen-Aurivillius related oxide structure composed of [Bi 2 O 2 ] layers sandwiched between two slabs of [X] ions, and the electrostatic potential difference between the slabs generates a static internal electric field (IEF). The static IEF in BiOX can effectively split and transit the photogenerated electrons and holes [61][62][63]. However, BiOX as a photocatalyst could be employed for the degradation of organic pollutants alone as its positive CB (conduction band) potential restricts it from being used for other photocatalytic applications such as H 2 generation, CO 2 reduction, N 2 fixation and organic synthesis.…”